Answer
Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear questioner, we would like to thank you for the great confidence you place in us, and we implore Allah Almighty to help us serve His cause and render our work for His Sake.
Answering your question, Dr. Muhammad Salama, PhD, Islamic Studies in English, Associate Professor at the Faculty of Islamic Sciences al-Madinah International University (Mediu), states:
A Muslim has only to follow the traditions of Prophet Muhammad (peace and blessings be upon him). No Muslim scholar has ever asked Muslims to follow all his opinions; simply because he is a human being and his opinion could be wrong, in spite of his sincerity and great endeavor to reach the truth. The opinions of scholars are just attempts to guide Muslims along the prophetic path.
For learned persons, they are aware of the principles of each school of Fiqh and one of them may choose to follow the principles of a specific school, because its principles seem to be the best in his view.
Still, however, in his search for the true opinion, he may adopt a different opinion in some cases, if he is not fully convinced with the opinion of the school he belonged to.
For lay people, they do not have the ability to distinguish between the principles of Fiqh Schools in order to choose the best in their sight. Therefore, a lay person asks a scholar whom he believes to be most knowledgeable and most pious and follows his fatwa. If there is a dominant Fiqh school in any country, usually scholars of that country follow the opinion of that Fiqh school.
Allah Almighty knows best.